Low-temperature extrusion or low-temperature freezing is a technology that has been recently developed and which has been used to confer enhanced organoleptic properties to frozen confectionery product. Examples of such frozen confectionery include ice cream, frozen milk shake, frozen yogurt, sorbet etc.
Such a method is described for instance in WO 2005/070225, WO 2006/099987, EP 0713650, U.S. Pat. No. 7,261,913 and more recently US 2007/0196553.
The products obtained by low-temperature extrusion have a particular microstructure as extensively described in Ph.D. Dissertation of Wildmoser J. submitted to the Swiss Federal Institute of Technology Zürich, 2004, “Impact of Low Temperature Extrusion Processing on Disperse Microstructure in Ice Cream Systems”.
Such products usually when aerated require stabilisation during and after production in order to render the products marketable. Conventional stabiliser and/or emulsifier systems have been traditionally used to give such products adequate stability.
However, these traditionally used ingredients are often seen as additives by the consumer and detract from a natural, healthy image which would be more appealing to the consumers.
EP 1400176 describes a conventional manufacturing process for frozen products comprising no traditional stabiliser or emulsifier. The traditional stabilisers or emulsifiers are replaced by soluble and insoluble fibres. However, it does not concern low-temperature extrusion methods of manufacture.
It would therefore be advantageous to develop a stabiliser system which can be used in low-temperature extrusion processes and which does not require non-natural additives. This poses a great challenge as not only should the product be stable under the processing conditions at varying overruns, but it should also maintain the superior sensory profile attributed to low-temperature extruded frozen aerated products.